New transmission networks, including ISDN and fiber optic transmission networks are providing larger bandwidth than were heretofore available for network users. The availability of larger bandwidths has spawned a wide variety of enhanced communications services including for example high resolution video.
It is likely that individual users of wide bandwidth networks will each have a plurality of advanced telecommunication devices such as full motion television cameras, document scanning devices, and document display devices. Such document display devices may include an interactive device such as a light pen which will permit telewriting.
One use of high bandwidth networks and associated user communication devices is video-conferencing. Conferences may be set up between a plurality of users each having one or more of the user devices discussed above. For example, four users may wish to participate in a video conference, in which each user can simultaneously display information received from the other three users.
In the past, the capability of video-conferencing systems was limited by the available bandwidth. Such prior art video systems are discussed in Brown et al, U.S. Pat. No. 4,004,084 and A. J. Seylor et al, "The APO TV-Conferencing Facility", Telecommunications Journal of Australia, Vol. 23, No. 3 (1973) pp. 216-225. In particular, such prior art telecommunications systems, did not contemplate the wide variety of equipment that is presently available.
One problem in providing video-conferencing among a plurality of users, each having, for example, some or all of a full motion television camera, a document scanning device, and a document display device, is that different users can be expected to have different equipment made by different manufacturers, which equipment will operate at different bit rates using different protocols. Thus, the network, even if it has an appropriately large bandwidth, will need the capability of collecting multiple asynchronous video, audio, graphic and data signals from a variety of sources and retransmitting such signals in a suitable form for display or detection at a plurality of receiving stations having a variety of receiving equipment.
Accordingly, it is an object of the present invention to provide a telecommunications interface which is capable of receiving a multiplicity of signal types from a multiplicity of sources and is capable of retransmitting the signals in a suitable format to one or more locations having a variety of receiving equipment. Such an interface is desirably capable of functioning at bit rates up to the gigabit/second range.